This is maybe one of the purest examples of the Bell Curve Meme in software engineering. The things you would do to the system Tailscale operates to eliminate all single points of failure (generally, and in the specific case where, where the "single point of failure" applies only to a small cohort of customers) would make the system less resilient, and increase failures.
replyGenerally, you do complex distributed systems without on-paper single-points-of-failure anywhere when you absolutely have to, because those systems don't have transient failures. That's not mesh networks like Tailscale at all.
As always: https://how.complexsystems.fail/
You don’t need the control plane most of the time. I had a zero downtime headscale upgrade because once the nodes negotiate through the control plane they can talk to each other all the time. The data plane is peer to peer.
replyIt’s problematic because you can’t run connections but it doesn’t stop the world.
What are some solutions to avoid database corruption being single points of failure? I can’t think of any off the top of my head. I don’t think people typically consider database corruption to be a kind of failure common enough to design for, unless you have unusual requirements.
replyThe general answer to this is Byzantine consensus, which cryptocurrency blockchains are designed to solve. If your nodes are willing to fail a little more politely (e.g. no lying, immediately crashing, etc) you can use something cheaper like raft/paxos.
replyBut yeah, it's a lot cheaper to build a reliable system than it is to be resilient.
The shard was already a way to make it not a single point of failure.
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